docs: Add release notes for v6.1.2

docs/mkdocs.yml

@@ -33,7 +33,7 @@ nav:
  - Build: build.md
  - Customization: customization.md
  - Release Information:
-     - main (WIP): release/main.md
+     - v6.1.2: release/6.1.2.md
      - v6.1.1: release/6.1.1.md
      - v6.1.0: release/6.1.0.md
      - v6.0.0: release/6.0.0.md

docs/src/release/main.md → docs/src/release/6.1.2.md

 ---
 date: "2023-12-05"
 ---
-## Changes from 6.1.1 to main (WIP)
+## Changes from 6.1.1 to 6.1.2
 
 ### Integrated Components